<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .container {
        width: 80%;
        height: 500px;
        margin: 0 auto;
        border: 2px solid #ccc;
      }
      .inner {
        width: 80%;
        height: 80%;
        background: #f19752;
        border: 2px solid #ee772f;
      }
      .item {
        width: 50px;
        height: 50px;
        background: #ec5149;
        border: 2px solid #eb3223;
      }
    </style>
    <style>
      /* 在这里完成作业 */
      .container,
      .inner {
        display: flex;
        justify-content: center;
        align-items: center;
      }
      .inner {
        align-items: flex-end;
      }
      .item {
        flex: 1 0;
      }
    </style>
  </head>
  <body>
    <div class="container">
      <div class="inner">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
      </div>
    </div>
  </body>
</html>

